How to: Installing rocker arm shafts - best way to get good seal

[ischmitz]

OK,

I have heard at least four different ways to install rocker arm shafts. Here it goes:

A: Install them with assembly lube
B: Install them dry and put some oil into the bushing bore
C: Use RSR seals and install dry
D: Use a tiny bit of Loctite 574 or Permatex in the grooves scrape off the excess Loctite with a razor blade and otherwise dry and put oil into the bore.

The guy recommending the Loctite method swears by it and said the RSR seals don't work since they get cut when sliding the shaft into the cam housing. Loctite would be the much better solution. I am leaning towards D. Any thoughts?

Ingo

[dtw]

I assume the idea is that a film of 574 is placed between the rocker shaft end and the cam carrier. But how is this accomplished by putting some 574 in the groove- wouldn't it just sort of sit there, not sealing against anything? Or do you apply enough 574 to get the grooves loaded up, so that it smears against the cam housing on install? How do you keep it off the rocker bore? I like the idea but I'm confused on how you execute it.

[Wayne 962]

I like assembly lube, and RSR seals - you won't have a problem with leakage...

-Wayne

[Rot 911]

I used the method Wayne explains here and in his rebuild book, but I did notice some of the seals did get cut when sliding them into the holes in the cam housing. But they weren't leaking without the seals so hopefully the seal will give a bit of added protection.

[ischmitz]

Originally posted by dtw
I assume the idea is that a film of 574 is placed between the rocker shaft end and the cam carrier. But how is this accomplished by putting some 574 in the groove- wouldn't it just sort of sit there, not sealing against anything? Or do you apply enough 574 to get the grooves loaded up, so that it smears against the cam housing on install? How do you keep it off the rocker bore? I like the idea but I'm confused on how you execute it.

By loading up the groove and using the razor blade to get the loctite flush with the shaft surface you get just enough squeeze out of the groove to seal the shaft ends against the cam housing. When you torque the rocker shafts the groove gets a little smaller. It won't smear into the bushing upon install area because you used the rasor blade and the squished out amount is so minimal. At least that's what I have seen when the guy showed it to me. He has done several motors that way and said he never had seapage on one so far. I kind of like the idea.

Ingo

[magic930]

How do you torque and at what torque are these rocker arm bolts? I just dissasembled mine and went through 2- 5mm allen wrenches in the process ahving to grind them down occasionly to get a new edge. #2 and #5 exhaust had to be drilled out because they were so darn tight. When reassembling these how do you measure a torque setting with an allen key, I dont think a standard torque wrench will fit into the space provided... unless you keep the 5mm bolt on the outside which is not the way mine were to begin with.

[ischmitz]

Walt recomended a long allen wrench with a T-handle and then tighten them really good. You feel when its tight. According to him the factory torque spec might work on a brand new engine but is way to low for a rebuild to get a good seal.

Ingo

[Rot 911]

You should be able to use a torque wrench. Make sure you install the head side of the bolt facing the thin wall side where the rocker shaft goes, then by use of extensions you can use a torque wrench with an allen socket.

[Doug Zielke]

I used RSR seals, and assembled everything *dry* as per Walt Watson of CE. The seals are fragile, and can get cut if you just jam the shaft in carelessly. I also used a bit of extra torque on the screws as recommended by Walt on his website. No leaks in over 6000 miles since the rebuild.

[kstylianos]

From www.competitioneng.com

C.E.s' war on oil leaks

911 Tech tip

Rocker shafts

It is my opinion that rocker arm/shaft installation is responsible for more 911 rebuild oil leaks than anything else.

Step 1: "Dry installation"

When you install your rockers you naturally put engine assembly lube on the rocker arm and shaft for break in.........right? Wrong!

Install each rocker and shaft dry, then after torqueing the shaft, then oil the rocker through the oil holes and either side of the rocker. You can still put cam lube on the cam and rocker face.

Step 2: "The torque"

I'm a fanatic about torque specs. I follow the factory bible to the letter 99% of the time. But this is one of the exceptions. The factory manual says the rocker shaft torque should be 1.8 kpm. Multiply that x 7.23 and it converts to 13 ft lbs. This spec is fine if you have the luxury of new cam towers and new rocker shafts, but that is a very rare occurrence. Usually the cam towers have been used at least once or twice before. So........you torque your shaft to 1.8 kpm and less than a thousand miles later it looks like your new engine was built by a hack. On used rocker assemblies increase the torque to 2.5 > 2.8 kpm and the rockers won't come loose and the engine stays dry!

I have been using this installation method since 1980 and it's always worked.

-Walt

[Wayne 962]

I disagree with Walt on the rocker shafts for this reason alone: Walt puts together an engine pretty quickly, meaning that it would be run shortly after assembly. Regular oil is good for assembly lube if the engine is going to be put together and run relatively quickly after. For a novice rebuilding his engine, I assume that it will take a longer amount of time. Assembly lube lasts a long time - motor oil tends to not. So, I recommended the assembly lube based on my assumption of who would be assembling the engine. Plus, the method I recommended is also used by many others, and also works well.

As for torque - if you use the RSR seals, the rockers don't leak. If they do leak, then you can always tighten up the rocker arms later on. I felt this was a better approach than potentially separating and damaging the aluminum cam tower housings.

Most engine rebuiders don't like using the seals, but I see no reason not to.

-Wayne

[Doug Zielke]

As far as lubrication is concerned....Walt suggested I assemble everything dry, then use a simple oil can to squirt oil on all the rockers, including the oil holes. Walt's da man!

[cstreit]

I'm not sure I'd feel good about putting Loctite on the rocker shafts...

1. Hard not to get it in places you don't want it.
2. Can you imagine CLEANING it out of the bores next time?
3. THe RSR seals and the Walt (extra torque) method work well.

I use assembly lube for the same reason that Wayne does... Haven't had a leak yet. (knock wood)

[snowman]

ITs really hard to argue with someone like Walt, who has much more experience than any of us on this forum. If he says dry, then dry it is. But I would question Walt very carefully, does he mean tri-chlor, acetone, dry or just have the oil wipped off?

But in all fairness it is up to the individual doing the engine for the final decision on how it is done. So he should be aware that rubber seals are ALWAYS installed wet. The reason is to help prevent tearing and ruining the seal. I think a good compromise is to use assembly lube on everything, but then wipe of off, so it is clean, but not totally dry, just a very fine film of stuff.

The concern about cutting the seal is very valid. I would take a little extra time with some sand paper and or a file to break any sharp edges before assembly.

The torque may have to be increased. This is evident upon assembly. If you feel the thing turning as you try to tighten it or if it appears stuck or not right it will need more torque. There is a sort of SOLID feel that you get when it tightens correctly. This is a learned feel so good luck here.

As to torque wrench, it was already answered in a previous post. You use an allen SOCKET on the end of an extension. YOu do this in a sequence that allows you access to each rocker, ie one end to the other. Planning is required here.

[marcesq]

I had rocker shafts that had shifted in the journels (4) which resulted in oil leaking ala exxon valdes.

I checked with the shop that I trust and read Walt's article. Shop said same thing as Walt. They did add that using regular allen wrenchs to hold with the 8 and tighten with the 5 and tighten until 8 will just about be pushed out of it's socket. Did add the RSR seals.

8 track days and a bunch of miles, still dry as a bone.

[ChrisBennet]

I've heard of people having trouble putting the seals in dry (tearing) but I've never had a problem in half a dozen rebuilds.
-Chris

[Superman]

I used the seals and was warned about them getting mangled as they slid in. I elected to put a light coat of silicon grease (Dow Corning 111) on them as I do on virtually all o-rings. Silicon grease is unusually slippery and those seals slid right in without any trouble or tearing. I'm not kidding on this. Silicon grease is the most slippery stuff in my garage.

I was also told that, once started, you should be able to tighten the shaft by using one of the allen ends, and not even holding the other end still. If the other end turns, then you can have problems. If the other end stays put while you torque, then the shaft should give no problems. I also heard that a torque value slightly higher than factory is necessary.

No leaks in about 50K miles.